Your rotator cuff is made up of the muscles and tendons in your shoulder. These muscles and tendons connect your upper arm bone with your shoulder blade. They also help hold the ball of your upper arm bone firmly in your shoulder socket. The combination results in the greatest range of motion of any joint in your body.
A rotator cuff injury includes any type of irritation or damage to your rotator cuff muscles or tendons. Causes of a rotator cuff injury may include falling, lifting and repetitive arm activities — especially those done overhead, such as throwing a baseball or placing items on overhead shelves.
About half of the time, a rotator cuff injury can heal with self-care measures or exercise therapy.